The invention relates to a transfer device for the transfer of a flat folding box to a succeeding conveyor device with simultaneous erection with a rotarily driven support part which is rotatable about an axis of rotation, and at least one rotarily driven further support part which is rotatable about the axis of rotation coaxially to the support part, wherein the support parts each support at least one retaining device and perform a rotary movement at a speed of rotation which varies during one revolution and an opposing relative rotation, wherein the folding box can be received in a receiving station by the retaining device and can be conveyed on a curved track to a transfer station and can there be transferred to the succeeding conveyor device.
Such a transfer device is used, for example, in a cartooning machine where it is first necessary to erect a folding box in the flat folded condition before feeding a product to be packed, and to make it available in a succeeding conveyor device which is normally designed as a belt or chain conveyor.
In a transfer device of known construction, as shown for example in DE 198 01 194 A1, the folding boxes are presented in stacked condition in a hopper, the lower folding box of each stack is gripped by a retaining device, which is normally designed in the form of a suction device, and removed from the hopper. The retaining device is fitted on a support part which forms a planetary part in a planetary gear so that the retaining device is fed on a cycloid track to the succeeding conveyor device and is deposited in a cell formed in it. During the movement along the cycloid track the folding box is erected by stops and an erection finger.
The design of the cycloid track, as opposed to a pure circular movement, has the advantage that during the cycloid movement a plurality of turning points are formed in which the retaining device is moved at reduced speed. This is necessary to guarantee precise removal of the folding box from the hopper, precise erection of the folding box and correct depositing of the folding box on the succeeding conveyor device.
It has been shown in practice, however, that in the case of a further increase in the output of the transfer device problems arise, particularly when removing the folding box from the hopper, since the forces acting there present the risk that the folding box gripped by the retaining device also pull out a plurality of folding boxes on top of them because of the high speed of removal, which boxes then fall loosely into the transfer device and may prevent the latter from operating. In order to provide a period sufficient for the folding boxes to be received by the retaining device a planetary gear with a very complicated structure with superimposed correction movements is required, which is very expensive to design and is therefore cost-intensive.
DE 198 45 384 A1 discloses a transfer device of the inventive kind. In such a transfer device a plurality of independent support parts are provided, each of which supports a retaining device in the form of a suction cup. The support parts are rotatable about a common axis of rotation and each has its own drive motor. This enables the retaining devices to be moved during a revolution at a variable speed of rotation and to perform a mutual relative rotation, as a result of which the movement processes can be adapted to the function required at any time, i.e. the receiving of the folding boxes or their transfer to the succeeding conveyor device. However, the design cost is very high and the transfer device is relatively expensive since each retaining device requires its own drive motor. Moreover, the number of retaining devices and hence the output of the transfer device are very limited for space reasons.
The object of the invention is therefore to provide a transfer device of the type mentioned which is of simple structural design and guarantees reliable transfer of the folding box to the conveyor device, even at high cycle numbers.